The invention relates to a lamp with a reflector and a light source.
Lamps as defined in the opening paragraph comprise a reflector which is shaped at one side for forming a desired beam of the light and at the other side has a comparatively small opening for accommodating the light source. The light source is introduced into this reflector neck and fixed therein, possibly after an alignment operation. Incandescent lamps and in particular gas discharge lamps may be used as the light sources. The light sources used in known lamps are fastened in the reflector necks by means of a cement. This leads to long process times in manufacture caused by a long drying time of the cement. The light source is aligned in the reflector, must be kept in the desired position, and is not fixed therein until after the drying time has elapsed. Cables for current supply can then be fastened. These cables are preferably passed through the opening of a ceramic tube which in that case is also provided in the reflector neck by means of a cement. Then the ceramic tube is filled up with silicone up to a first cable lead-through. The cable lead-throughs are then closed with cement, and the ceramic tube is filled up with silicone. A long drying and curing time is required for setting of the cement and the silicone. Lamps according to the present state of the art accordingly require the very long process times described above and involve the problematic uncertainty whether during this time the alignment of the light source in the reflector may be disturbed, which would result in defects. In spite of an intricate and expensive alignment during the drying time, shifting may yet occur, which would lead to an incorrect lamp. The fixation by means of cement, moreover, is of very limited use only for automotive applications because of the hygroscopic properties of the cement.
It is accordingly an object of the invention to provide a lamp which has improved operational characteristics combined with a simplified manufacture.
This object is achieved in that a sleeve is provided for fastening to the reflector neck and for accommodating the light source. A mechanical fastening of the light source to the reflector can be achieved in a surprisingly simple manner by means of an added sleeve. This eliminates the disadvantages of the fastening in known lamps without detracting from the possibilities of aligning the light source in the reflector. Such a sleeve may be utilized for a plurality of lamps comprising a reflector and a light source through a suitable choice of its shape. The shape of the sleeve is chosen such each time that on the one hand it can be fastened to the reflector neck and on the other hand can be fixedly connected to the relevant light source. The reflector may have any shape as desired, adapted to the relevant application (for example, in motorcars, for exterior or interior lighting). It is also possible to use any types of light sources required such as, for example, halogen incandescent lamps or gas discharge lamps. The fixation of the sleeve to the reflector neck and to the light source is preferably constructed as a clamping joint. Other connection possibilities, however, are also conceivable, as long as they provide a fixation of the light source in a defined position in the reflector.
In an embodiment of the invention, a collar is provided for fastening to the light source and for fixing the light source in the sleeve. A particularly simple possibility for accommodating the light source in the sleeve is provided by a collar which is preferably fastened to the light source by means of a clamping connection. Preferably, the material chosen for the collar is a weldable stainless steel, so that the collar can be connected to the sleeve by means of laser welding. The collar may first be provided on the outer bulb of the light source, on the so-called exhaust tube, or it may be clamped onto the outer bulb in one process while being fixed to the sleeve. The shape of the collar is chosen such that it can be easily provided on the outer bulb and clamped thereon. Furthermore, it should be so designed that it can be moved in the sleeve, aligned, and finally fixed.
In an advantageous further embodiment, a cap is provided for fixing the collar to the sleeve. The cap may be provided as an additional component so as to facilitate a better joint between the collar and the sleeve. In particular, a weldable stainless steel (for example a chromium-nickel steel) is again used as the material for the cap. The shape of the cap may be adapted to the application of the lamp in question, taking into account a suitable contact with the sleeve and the collar so as to guarantee a simple mounting and fixation (preferably by laser welding).
In a preferred further embodiment, the sleeve is fastened to the reflector neck by means of a clamping device, and a clamping element is provided in the sleeve and a receptacle is provided at the reflector neck. The clamping device provides a particularly simple possibility for mounting with a good accuracy in retaining the position. The clamping device is formed by a clamping element and a receptacle into which the clamping element clamps itself. One or several metal strips bent or stamped in inward direction from the sleeve itself may be used as the clamping element. It is alternatively possible, however, to provide a separate clamping element in the sleeve. The receptacle of the reflector neck is so shaped that the clamping element fits into it, and the sleeve is fixed to the reflector by matching shapes. Suitable for this, for example, is a circumferential groove cut into the reflector neck with a width and depth adapted to the clamping element used. Again, alternative embodiments are conceivable within the scope of the basic idea of the invention.
Particularly advantageous is a lamp according to the invention wherein the collar is of tubular or spherical shape. The shape of the collar is always chosen such that it is capable of holding the light source, in particular by means of a clamping connection to its outer bulb. The outer shape may be adapted to the desired kind of alignment and connection to the sleeve. A tubular collar may be clamped on the outer bulb of the light source and may easily be connected to a sleeve which has a round internal diameter. The spherical collar is also introduced into the sleeve and can still be adjusted by means of pivoting movements.